A band saw machine includes a working platform, a cutting machine, a vertical displacement element causing the cutting machine to move vertically, a height sensor and a central processor. The working platform includes a reference plane for placing a workpiece. The cutting machine includes a driving wheel, a driven wheel, a band saw wound on the driving wheel and the driven wheel, and a motor that electrically drives the driving wheel. The band saw includes a starting cutting tooth and a processing cutting tooth sequentially arranged. The height sensor detects a starting cutting point of the workpiece farthest from the reference plane. The central processor receives information of a position of the starting cutting point, and controls a displacement speed of the vertical displacement element and a first rotational speed of the motor to cause the starting cutting tooth to first cut at the starting cutting point.